package com.cgfay.picker.widget.subsamplingview.decoder;

import java.io.InputStream;
import java.util.List;

import android.content.ContentResolver;
import android.content.Context;
import android.content.pm.PackageManager;
import android.content.res.AssetManager;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.BitmapFactory;
import android.graphics.BitmapRegionDecoder;
import android.graphics.Point;
import android.graphics.Rect;
import android.net.Uri;
import android.text.TextUtils;


/**
 * Default implementation of {@link ImageRegionDecoder} using Android's
 * {@link BitmapRegionDecoder}, based on the Skia library. This
 * works well in most circumstances and has reasonable performance due to the cached decoder
 * instance,
 * however it has some problems with grayscale, indexed and CMYK images.
 */
public class SkiaImageRegionDecoder implements ImageRegionDecoder {

  private BitmapRegionDecoder decoder;
  private final Object decoderLock = new Object();

  private static final String FILE_PREFIX = "file://";
  private static final String ASSET_PREFIX = FILE_PREFIX + "/android_asset/";
  private static final String RESOURCE_PREFIX = ContentResolver.SCHEME_ANDROID_RESOURCE + "://";

  @Override
  public Point init(Context context, Uri uri) throws Exception {
    String uriString = uri.toString();
    if (uriString.startsWith(RESOURCE_PREFIX)) {
      Resources res;
      String packageName = uri.getAuthority();
      if (context.getPackageName().equals(packageName)) {
        res = context.getResources();
      } else {
        PackageManager pm = context.getPackageManager();
        res = pm.getResourcesForApplication(packageName);
      }

      int id = 0;
      List<String> segments = uri.getPathSegments();
      int size = segments.size();
      if (size == 2 && segments.get(0).equals("drawable")) {
        String resName = segments.get(1);
        id = res.getIdentifier(resName, "drawable", packageName);
      } else if (size == 1 && TextUtils.isDigitsOnly(segments.get(0))) {
        try {
          id = Integer.parseInt(segments.get(0));
        } catch (NumberFormatException ignored) {}
      }

      decoder = BitmapRegionDecoder.newInstance(context.getResources().openRawResource(id), false);
    } else if (uriString.startsWith(ASSET_PREFIX)) {
      String assetName = uriString.substring(ASSET_PREFIX.length());
      decoder =
          BitmapRegionDecoder.newInstance(
              context.getAssets().open(assetName, AssetManager.ACCESS_RANDOM), false);
    } else if (uriString.startsWith(FILE_PREFIX)) {
      decoder = BitmapRegionDecoder.newInstance(uriString.substring(FILE_PREFIX.length()), false);
    } else {
      InputStream inputStream = null;
      try {
        ContentResolver contentResolver = context.getContentResolver();
        inputStream = contentResolver.openInputStream(uri);
        decoder = BitmapRegionDecoder.newInstance(inputStream, false);
      } finally {
        if (inputStream != null) {
          try {
            inputStream.close();
          } catch (Exception e) {}
        }
      }
    }
    return new Point(decoder.getWidth(), decoder.getHeight());
  }

  @Override
  public Bitmap decodeRegion(Rect sRect, int sampleSize) {
    synchronized (decoderLock) {
      BitmapFactory.Options options = new BitmapFactory.Options();
      options.inSampleSize = sampleSize;
      options.inPreferredConfig = Config.RGB_565;
      Bitmap bitmap = decoder.decodeRegion(sRect, options);
      if (bitmap == null) {
        throw new RuntimeException(
            "Skia image decoder returned null bitmap - image format may not be supported");
      }
      return bitmap;
    }
  }

  @Override
  public boolean isReady() {
    return decoder != null && !decoder.isRecycled();
  }

  @Override
  public void recycle() {
    decoder.recycle();
  }
}
